The Animal Imaging Core provides services for molecular imaging of rodent models of human cancer. The Core provides investigators with non-invasive, high-resolution quantitative imaging-based capabilities for metabolic and genetic characterization of tumors and their microenvironment, including in vivo trafficking of tumor cells. This is accomplished by monitoring of "directly-targeting" probes and of the expression of single and multi-modality reporter genes using optical (bioluminescence and fluorescence), radionuclide (PET, SPECT, and autoradiography), MRI/MRS, CT, and US imaging. These imaging techniques are wellestablished at MSKCC for small-animal imaging studies. They are quantitative and non-invasive and thus readily adaptable to longitudinal studies. The Animal Imaging Core also provides investigators with access to critical ancillary equipment and services such as a Fuji Film BAS-180011 phosphor-plate digital autoradiography system, a digital-camera-equipped Olympus B 201 fluorescence microscope with motorized stage, and a Microm HM500M cryostatic microtome. As part of a major expansion and modernization of MSKCC's infrastructure (Phase 1), part of the Imaging Core has recently re-located to the C4 level within the Vivarium of the new Zuckerman Research Center. This area provides enhanced biosecurity and functionality and houses our R4 and Focus 120 microPET dedicated high-resolution small-animal (rodent) PETs, new MS 200 optical imaging system, microCAT II dedicated small-animal (rodent) CT, and X-SPECT dedicated small-animal SPECT-CT. The existing MS 100 optical imaging system and recently installed Vevo 770 ultrasound system have been re-located to refurbished space on the 12th floor of the Rockefeller Research Laboratory providing improved access to the primary users of these two systems. The Imaging Core's 4.7-T 40-cm bore and 7.0-T 31-cm Brucker NMR imaging and spectroscopy systems are currently located in the MRI Building. In Phase 2 of MSKCC's capital expansion and modernization, all of the foregoing instrumentation of the Imaging Core will be consolidated in spacious, state-of the-art quarters with the Center's vivarium.